Rather than relying on a thermostat,
socially driven HVAC optimization uses
software on each occupant’s computer or
handheld device to determine whether
the user is too hot, too cold or comfortable. The feedback is sent to the building automation system, which triggers
a large flow of conditioned air into the
space to provide instant relief. After a
short period, the airflow and temperature revert to an energy-saving mode
while waiting for more feedback.

Over time, the system analyzes feedback trends to determine how best to
keep occupants comfortable while saving
energy. It also learns how to relax temperature setpoints in unoccupied spaces.

The technology is designed for variable air volume (VAV) systems that are
controlled by digital energy management
tools, though it can also be paired with
other types of HVAC.

Successes and Hurdles

The socially driven HVAC technology
was installed in the Federal Building and
U. S. Courthouse in Phoenix in March
2014. The eight-floor facility is home to
about 350 occupants and covers 289,000
square feet. Like about 50% of GSA’s
portfolio, this building has a VAV system
controlled by digital energy management.
It also features a wide variety of tenant
spaces to help evaluate the technology’s
usefulness thoroughly, as well as a robust
BAS system. Occupant surveys before
installation and five months after deployment were used to determine comfort.

Over the summer, the system noted an
average rise of 2 degrees F., from 75 to 77.
This helped save energy during the cooling season while maintaining comfort.

Because the solution is subscription-based, a typical payback calculationdoesn’t apply, GSA notes. Instead, thereport compares the annual energy costsavings and square footage to the sub-scription cost to determine a “break even”threshold at which the technology paysfor itself. The vendor provided a subscrip-tion range of 12-60 cents per square footper year depending on the size, complex-ity and duration of the service.

GSA calculates the break even pointof the subscription cost for large officebuildings at roughly 9-16 cents per squarefoot depending on the climate zone. ThePhoenix courthouse would likely save anestimated $6,700 in energy costs annu-ally if the technology was used all year,GSA finds – a significant savings, but notenough to justify the annual subscriptionsavings doesn’t include the decreased useof personal space heaters and fans. Staffdescribed the value vs. energy cost as “anight and day difference.” The buildingwas already meeting its energy require-ments before the installation, but thetechnology could be a useful tool in a suiteof energy savings programs, GSA says.

“The socially driven HVAC technology should be considered for facilities
where thermal comfort is a priority,”
GSA notes in the report, stating that
the technology’s economic viability is
unclear. “It will be most effective in
facilities with high energy costs, narrow
deadbands (the range in which neither
heating nor cooling is turned on), and a
significant portion of space that is only

OCCUPANTS OF A FEDERAL BUILDING reported far fewer complaints about indoor temperature
after thermostats were replaced with software that allowed them to input their comfort level.